The wireless portable Internet is a next generation communication system for further supporting mobility in addition to a short range data communication system which uses fixed access points APs such as the conventional wireless local area network (LAN). Various standards have been proposed for the wireless portable Internet, and the international standardization on the portable Internet is in progress with reference to the IEEE 802.16.
The authentication and authorization standard defined by the IEEE 802.16 establishes authentication functions for stations in the wide area network configured with wireless networks. In particular, since the subscriber station (SS) authentication function standardized by a privacy layer of the IEEE 802.16 is defined only for SSs within a fixed network, it is inappropriate for the authentication function to apply SSs or subscribers to be capable of supporting mobility, which is a current trend of mobile services. That is, since the authentication function does not specify detailed functions in a base station (BS) which describes messages and procedures for authenticating the subscriber stations on the basis of the fixed networks, additional functions of the base station are required for the motile services. The requirement of additional functions requires the base station to have profiles of all subscribers who currently receive services, and the same requires a function of API for the CA interface or a function of accepting authentication clients for interface with an authentication server when the base station does not have the profiles.
Also, since the conventional authentication for the subscriber stations on the fixed network is based on digital certificates, the conventional authentication process is restricted to servers which perform certificate-based authentication when a user accesses an authentication server to be authenticated, and the conventional authentication process needs other improved functions for security of the base station since the conventional standard defines that the base station distributes a security key between the subscriber station and the base station.